Tool attachment



June 17, 1941. JOHNSON 2,245,676

TOOL ATTACHMENT Filed June 11, 1940 Patented June 17, 1941 UNITED STATESp re r oF-FIcE 7 Ciaims.

This invention relates to improvements in machine tools and moreparticularly to punch and die supports and retainers.

One former the invention discloses a support and retainer for punchesand dies in which the punch and die are firmly and rigidly held inposition of use and yet may be readily removed and replaced asfoundconv-enient or necessary.

It has been the general practice, prior to this invention, in the makingof tools of this class, to provide a punch or die mounting plate with aledged-aperture for receiving a'correspondingly shaped portion-of apunch or die. The aperture in the plate, together with the correspondingparts of a punch and die, must be accurately machined to prevent eventhe slightest relative displacement when these parts are assembled foruse. 'The purpose of providing an enlarged portion on the punch or diethat interfits with an opening in the plate is to prevent axialdisplacement after the punch and die have cooperated in a piercingoperation.

Several attempts have been made to simplify punch and die structures .byeliminating the enlarged end that interfits with the mounting plate andsubstituting therefor wedge or key means for preventing displacementafter the piercing operation. This structure was intended to have theadvantage of ready removability of the punch and. die as foundconvenient or necessary to replace a damaged tool or change the type oftool. In practice, however, it was found that the means for securing thepunch and die in this plate, under the severe pounding to which thesetools are subjected, caused jammingand wedging of the once disassociableparts to such an extent that it was more diflicult to separate a punchand die from its plate by this method than would have been required hadthe older and-more generally known type of mounting for punch and diesbeen resorted to.

lt-is-one of the objects of the present invention to provide improvedmeans for retaining a .punch or die in a support of the type now incommon usein machines of this class.

Another object of the invention lies in the provision of retaining meansfor a punch or die that greatly simplifies the manufacture of theseparts without-sacrifice of accuracy.

Another object .of the invention lies in the provision of means forretaining a die or punch in a supporting member that is inexpensive tomanufacture and is readily applicable to machines of this class now inuse.

Another object of the invention lies in the plate l'2.

provision of means for rigidly mounting a punch or die in such a mannerthat, as found convenient or necessary, the punch or die may be readilyremoved.

Other objects andadvantages of the invention will be more fullyunderstood and appreciated from a consideration of the followingspecification, taken in conjunction with the accompanying drawing; andin'which Figure 1 is a vertical sectional view through a punch supportand retainer illustrating one form of the invention;

Figure 2 is a vertical sectional view of a'die support and retainerembodying one form of the invention, this figure being positioned withrespect to Figure 1 to indicate the relationship of punch and die;

Figure 3 is a perspective view of a punch and retainer ring priorto'assembly;

Figure 4 is a horizontal sectional view of a die and retainer ring,being taken substantially on the line 4-4 of Figure '2;

Figure 5 is a Vertical sectional view of a modification of a punch andretainer;

Figure 6 is a fragmentary vertical sectional view illustrating amodification of the punch securing means; and

Figure 7 shows a retainer ring formed in two parts. Reference is now hadto the drawing wherein the numeral 10 is employed to designate thatportion of a :press in which punch tools are mounted. A conventionalmember II is adapted to mount a punch retaining plate 12, suitable studsI3 being provided for this purpose. As is conventional, accuratelyaligned openings l4 and 16 are made in the support and plate II and I2,and dowels 11 inserted into these openings serve to prevent lateraldisplacement of the plate.

The plate I2 is formed with one or more vertical openings ['8 that arethe diameter of the body portion ['9 of a punch 21. Adjacent the upperface of the plate is an opening 22 centered with the opening 18 and ofslightly larger diameter. The meeting edges of the walls of openings l8and 2-2 are formed to provide a rounded annular shoulder 23. The punch2i, beneath the body portion I9, is formed with a piercing end 24 of anydesired shape and size. Adjacent the upper end of the body portion l9 asemi-circular annular groove 26 is produced. The lower edge of thisgroove is spaced from the fiat top 2-1 of the punch a distancesubstantially equal to the depth of the opening 22 of the A splitretainer ring 28 is adapted to be sprung into place in groove 26 of thepunch 2|. This ring when so positioned projects beyond the body portion[9 and is engageable with the annular shoulder 23.

When it is desired to assemble one or more punches embodying theinvention, each punch is fitted with a ring 28, as described, andprojected into the opening l8 of the plate I2 from its upper face. Thering 28 serves as a stop to locate the punch with the fiat top 21 flushwith the upper face of the plate 12. The plate I2 may now be secured tothe support II by studs l3, after which, and in accordance with theconventional practice, dowels I! are inserted into the openings providedtherefor. It will be noted that the top or head 21 of the punch bearsdirectly against the support I I, thus no strain is placed on theretainer ring 28 during a perforating operation. However, on the upstroke-that is during removal of the piercing end 24 from the piercedmaterialthere is a downward pull on the punch and this is resisted bythe ring 28. There can 'be no tendency for the retainer ring 28 to jamwhen it is desired to remove the punch, since the force applied in thepiercing operation is in a direction to release the retainer ring and,furthermore, suificient surface of the body portion I3 is engaged withthe walls of the opening E8 of the plate to prevent misalignment of thepunch with respect to the die, and distortion of the ring.

Under circumstances where special accuracy is required, 'it is founddesirable to utilize removable dies such as indicated by the numeral 29in Figure 2 of the drawing. These dies are each provided with an opening3| corresponding to the size and shape of the piercing end 24 of thepunch. At the lower end of each die is an annularrecess 32,substantially identical with the recess 26. A split ring 33 is mountedin the recess and the die and ring inserted in the opening in a plate 34mounted on a support 36 in the manner already described in connectionwith support I I and plate l2. The ring 33 takes no part of the force ofthe piercing blow of the punch but, rather, serves to prevent upwardwithdrawal of the die from the plate 34 when the punch is being removedfollowing the piercing operation. Since no damage can occur to therecess of the die, ring 33, or walls of the opening in the plate 34, thedie may be readily removed when the plate has been removed from thesupport 36.

Attention is now directed to Figure of the drawing wherein amodification of the structure above described is shown. In thisinstance, a support 31 mounts a plate 38 in the conventional mannershown. Plate 38 is provided with one or more punch receiving apertures39. A punch 4| is provided adjacent its piercing end 42 with an annularrecess 43 into which is fitted a split ring 44. The punch is then placedin the opening 39, the upper end contacting the support 31, ring 44being adjacent to the under face of the plate 38. A small plate 46 isprovided, being formed with a central opening 41, the diameter of thebody of the punch. The upper end of this opening is enlarged, as at 48,to receive the retainer ring 44. Suitable studs 49 secure the plate 46to the plate 38. In this modification it is to be noted that the body ofthe punch 4| has unbroken engagement with the walls of the plate openingthroughout the depth of said plate. Thus the punch is firmly supported.Also the force applied to the punch during the piercing operation is tono extent conveyed to the plate 46 or retainer ring 44 and,consequently, at such time as it is desired to remove the punch, nodifficulty is encountered by reason of the parts being out of alignmentor in any way distorted.

Referring to Figure 6 of the drawing, it will be noted that a supportingplate 50 may be formed with an upper enlarged opening 5|, the walls ofwhich are slightly tapered and terminate in a shoulder 52. In thismodification oi the invention an annular recess 53 of somewhat differentproportions is provided in a punch 54. This recess receives acorrespondingly shaped portion of a split retainer ring 56. By reason ofthe slightly tapered walls of the opening 5|, the retainer ring, whenthe punch is projected through the plate 50, is caused to firmly engagethe walls of the recess 53. Here again it will be noted that the meansfor securing the punch against removal following the piercing operationin no wise receives any of the force applied during the piercingoperation. It is also contemplated, as suggested in Figure '7 that aretainer ring 51 may be provided which will be made in two or moreparts, as may be found most suitable under certain conditions of use.

Although applicant has shown and described only one useful applicationof the invention, it will be understood by those skilled in the art thatthe structure may be modified without departing from the spirit andscope of the invention as defined in the hereunto annexed claims.

Having thus set forth my invention what I claim as new and for which Idesire protection by Letters Patent is:

1. A tool attachment comprising a plate having an opening therethrough,a tool having a diameter such as to engage the Walls of said opening,and means carried by said tool, said means being firmly engageable withsaid plate in one direction to prevent withdrawal of said tool from saidopening and freely disassociable from said plate in the oppositedirection.

2. A tool attachment comprising a plate attachable to a supportingmember, said plate having an opening therethrough, a tool having a bodyportion of a diameter to snugly engage the walls of said opening, meanson said body portion cooperating in one direction with a portion of thewalls of said opening to secure said tool against axial displacement andin the opposite direction to be readily disassociable from the walls ofsaid opening.

3. A tool attachment comprising a plate attachable to a supportingmember and having a tool receiving opening therein, an annular shoulderadjacent one end of said opening, a tool having a body portionprojectable through said opening, and means on said tool engageable inone axial direction of said tool with said shoulder whereby to preventdisplacement of said tool from said plate.

4. A tool attachment comprising a plate attachable to a supportingmember and having a tool receiving opening therein, an annular shoulderformed by an enlargement adjacent one end of said opening, a tool havinga body portion projectable through said opening, said body portionhaving an annular groove, a split ring engageable with said groove, saidring being located within the enlargement and adapted to abut saidshoulder to secure said tool against axial displagement in one directionwith respect to said pla e.

5. A tool attachment comprising a plate attachable to a supportingmember and having a tool receiving opening therein, a tool having a bodyportion of a diameter to snugly engage the walls of said opening, ashoulder formed by an enlargement of said opening adjacent saidsupporting member, a retainer ring secured to said tool adjacent one endof said body portion, said ring being of a diameter to enter theenlargement of said opening and engage said shoulder whereby to securesaid tool against displacement from said plate in one direction.

6. A tool attachment comprising a plate attachable to a supportingmember and having a tool receiving opening therein, a tool having a bodyportion of a diameter to snugly engage the walls of said opening, oneend of said body portion being surfaced to receive the operating forceof said member, a shoulder formed by an enlargement of said openingadjacent said supporting member, said body portion having an annulargroove, a split ring engageable with said groove, said ring being of adiameter to enter the enlargement of said opening and engage saidshoulder whereby to secure said. tool against axial displacement fromsaid plate in one direction.

'7. A tool attachment comprising a plate attachable to a supportingmember and having a tool receiving opening therein, a tool having a bodyportion of a diameter to snugly engage the walls of said opening, oneend of said body portion being substantially flat to abut and receivethe operating force of said supporting member, said opening being ofenlarged diameter adjacent said member and producing an annular shoulderin the walls thereof, the body portion of said tool being formed with asemi-circular annular groove, a ring of generally circular cross sectionengaged with and projecting beyond the walls of said groove, theprojecting portion of said ring being engageable with the shoulder ofsaid opening whereby to secure said too1 against axial displacement inone direction from said plate.

EMIL M. JOHNSON.

